If there’s something I don’t give a fuck about but that exists in that gray area of potentially hurting someone else’s feelings no matter how honest and polite I am, I simply chalk it up to a “personal policy.” As in “I have a personal policy against donating to Kickstarter campaigns, because if I donate to one, I feel like I have to donate to them all. I just can’t afford it, and if I had to choose, I wouldn’t want anyone I love to think I value them more or less than anyone else.”
This is the best thing to remember and use.
